Embodiments of the disclosed technology relate to an electrowetting display.
The principle of the electrowetting display technology is related to electrowetting phenomenon or electrocapillary phenomenon, in which the free surface energy of a fluid can be changed when the fluid is subject to an influence of an electric field, so that the distribution area of the fluid in a pixel unit can be changed and thus a corresponding change can occur in the pixel unit to achieve a display effect. The electrowetting display technology has drawn a lot of attention due to its characteristics such as low power consumption, wide viewing angle and high response speed.
FIGS. 1A and 1B are schematic views of a typical conventional electrowetting display pixel unit. FIG. 1A shows the state without application of an operational voltage applied, in which a first fluid having a color forms a flat thin film layer 12 between a transparent polar fluid layer 11 and a waterproof insulating dielectric layer 13, and at this time, this display state of the pixel unit is at a dark state. FIG. 1B shows the state when an operational voltage is applied between an underlying electrode 14 and the polar fluid layer 11, in which the tensile force at the contact surface between the first fluid 12 and the dielectric layer 13 will change, and as a result, the original stationary state is no longer stable, so that the first fluid 12 is moved sideward to expose most portion of the pixel region (bottom), and at this time, a partially transparent pixel dot is formed and this display state of the pixel is at a bright state.
The change of the contact angle between fluids is a phenomenon that an electrolyte solution contracts or extends on another a fluid or substrate under the influence of an electric field. The electrowetting display technology uses the mechanism of electrowetting phenomenon, and displays by controlling an ink drop to extend or contract in pixel unit. The ink may have two functions:
1. a blocking function, generally applied for black-white display, in which the first fluid is black ink, and black color is displayed in a dark state and white color is displayed in a bright state.
2. a displaying function, generally applied for color display, in which the effect of color display is achieved by using the color of the first fluid itself.
Although the conventional electrowetting display technology has advantages, a very satisfying color display effect could not be achieved yet at present.